Various thermoplastic resins are used as molding materials and, for example, EVOH is excellent in terms of transparency, gas barrier properties, aroma retention properties, solvent resistance, oil resistance and the like, and such properties are exploited for use in forming films and sheets, as well as containers such as bottles, serving as food packaging materials, medical packaging materials, industrial chemical packaging materials, agricultural chemical packaging materials, and the like.
EVOH in the form of pellets is melted in an extruder and molded into films, bottles or the like. Thus, if the flowability of the pellets is low, a phenomenon known as bridging occurs, in which the pellet particles form arch structures with each other and clog the supply port area of the extruder (inside the hopper), such that the pellets will not readily be discharged from the discharge port, and the feed rate may become unstable. As a result, the film thickness of the molded product may fluctuate or the appearance may be poor.
Here, Patent Literature 1, for example, states that EVOH pellets in which the ratio of the average diameter to the average length is great, which is to say, pellets having relatively short pellet length, have excellent feed stability, and that films formed using these pellets have excellent quality, with few fish eyes.
Meanwhile, it is known that EVOH even more effectively exhibits functions such as gas barrier properties mentioned above as a result of being designed to be as close to a dry state as possible. Here, so as to ensure a dry state for the EVOH, Patent Literature 2, for example, discloses that low water-content EVOH pellets can be manufactured by mixing EVOH and a desiccant in the molten state, extruding this as a strand form, and cutting this with a specific water cooling process.